Casein hydrolysates are used for protein fortification, e.g. in sports drinks, and in other dietary drinks, dry blended beverages, nutritional bars, infant formula, etc. Casein hydrolysates have in some cases been found to be less allergenic than whey protein hydrolysates which make them potentially more useful in, e.g., infant formula. Casein hydrolysates may be manufactured using proteolytic enzymes to hydrolyse the casein. In industrial manufacturing of casein hydrolysates, high solubility or suspendability of the hydrolysed protein is important both from a processing point of view, from a pure yield/economical point of view and because of mouthfeel and sensory attributes. It was therefore an object for the present inventors to identify proteolytic enzymes which are useful for preparing casein hydrolysates having a high solubility, such as a high solubility at low pH and/or a high solubility at low or moderate degree of hydrolysis.
Endopeptidases found to be applicable according to the present invention have been previously described. E.g., the endopeptidase derived from Nocardiopsis sp. NRRL 18262 is disclosed in WO88/03947 (here the strain is referred to as Nocardiopsis sp. strain 10R) and WO01/58276. Other related endopeptidases which are useful according to the invention are disclosed in WO88/03947, WO04/111220, WO04/111222, WO04/111223, WO05/123911, and WO04/072279.